1. Field of the Invention
The present invention relates to improvements to an apparatus for controlling a throttle valve electronically by an actuator such as an electronic motor in an internal combustion engine.
2. Description of the Background Art
Recently, control for a throttle valve of an internal combustion engine having multiple functions has been realized. The multiple functions are 1) interlocking with an accelerator pedal depressed by an operator; 2) traction control so as to reduce an opening angle of the throttle valve to reduce slips of vehicular tire wheels during a vehicular acceleration; and 3) automatic cruise control to maintain a constant vehicular speed with the accelerator pedal open or not depressed. Additionally, a fail safe structure is provided such that an overrun of engine revolutions is suppressed with the opening angle of the throttle valve held at a minimum position during a failure of the engine.
Japanese Patent Application First Publication No. Showa 62-284932 published on Dec. 10, 1987 exemplifies a previously proposed throttle valve opening angle controlling apparatus in which traction control is carried out.
In the disclosed Japanese Patent Application, a restricting plate is located between the throttle valve shaft bearing on the motor side and a gear mechanism that transmits the rotation of the motor to the throttle valve shaft.
However, in the previously proposed throttle valve opening angle controlling apparatus, since the motor is not covered by a casing, deterioration of the mechanical parts is induced by the entry of the foreign matter, and corrosion, thereby reducing the reliability.
The design must also be coaxial with the motor and the throttle valve, and the length of the apparatus increases in length, which may cause the reduction of the anti-vibration.